1. Field of the Invention (Technical Field)
The present invention relates to a method and an apparatus permitting users physically located before different input/output devices to use collaboratively and simultaneously a single executing copy of an application computer program. The method of the invention may be employed with any communication protocol employing a clientserver control structure.
2. Background Art
In modern society, it has become increasingly important to permit individuals to work together while separated by distance from one another; hence the development of the telegraph, telephone, teleconferencing systems, facsimile machines, and computer networks. In a society increasingly dominated by the access, creation, and sharing of information, the computer has become an important tool in the day-today activities of workers in all segments of industry. Problems arise today when two or more employees working on a project together using computers must travel away from each other. Typically, the employees work separately on aspects of the common project, communicate their results by phone and/or computer, and eventually merge their separate work in some manner.
Most existing computer application programs are designed for use either by a single user or a group of users physically located before a single station having a single set of input/output devices. Application programs intended for simultaneous collaborative use must contain tailor-made computer instructions permitting such use. If an existing single-user program is to be converted to permit simultaneous collaborative use, the program must be rewritten at an enormous expenditure of time and resources.
Two approaches exist addressing this problem. The first approach, disclosed in U.S. Pat. No. 4,939,509, entitled "Data Conferencing Arrangement for Stations Having Keyboards and Displays, Using a Keyboard Buffer and a Screen Buffer," to Bartholomew et al., is non-general in that each user station must have no more and no fewer input/output devices than a display screen and a keyboard and in that the approach requires that the control means access keyboard buffers and screen buffers. The control software under this approach must be substantially rewritten for each operating system under which it would run. Furthermore, the approach provides no means for users to collaboratively use a plurality of application programs.
A second approach requires special control software executing separately for each station engaging in collaborative use of an application program. See S. R. Ahuja et al., "A Comparison of Application Sharing Mechanisms in Real-Time Desktop Conferencing Systems," Conference on office Information Systems, Apr. 25-27, 1990, ACM SIGOIS Bulletin, Vol. 11, Nos. 2 and 3, pp. 238-48; S. R. Ahuja et al., "The Rapport Multimedia Conferencing System," Conference on office Information Systems, Mar. 23-25, 1988, ACM Press Order Number 611880, pp. 1-8; J. R. Ensor et al., "The Rapport Multimedia Conferencing System--A Software Overview," Second IEEE Conference on Computer Workstations, IEEE Computer Society Press Catalog Number 87-80440, pp. 52-58. While this separate control software permits greater flexibility than provided by the method of the present invention, it requires substantial additional overhead processing for each station and is concomitant greater potential for errors to be introduced in the collaborative use.
The present invention permits physically isolated employees to collectively work using a single executing copy of any application program they are employing to do their work. The employees simultaneously see the output from the application. Each can manipulate data using the application to add new elements to the work, correct mistakes of colleagues, or make comments to the other collaborators. The employees may also simultaneously use more than a single application program collaboratively, for instance a CAD program to design a "widget," a desktop processing (DTP) program to edit a user manual for the widget, and a conferencing program to exchange comments.